Tool clearance overlay



Dec. 22, 1964 P. H. KACH Tool. CLEARANCEQVERLAY Filed Jan. 4, 1962FLYING PERSONNEL |950 gfl'oPEN ENQ WRENCH RAI-"TOOL SCALE 95THPERcr-:NTILE WADC. 52-

INVENTOR. PETER H. l-(ACH' ATTO RNEH United States Patent Ohlce ldl?Patented Dec. 22, 1964 3,161,957 EG-GL CLEARANCE @VERLAY Peter El. Each,Syracuse, NX. (l2ill2 Galena Road, Rockville, Md.) Filed dan. 4, 1%2,Ser. No. 164,33@ 4 fClairns. (Cl. 33l) This invention relates to adevice for assisting designers of apparatus requiring the use of tools,such as wrenches and the like for assembly, disassembly and servicing,in providing adequate access for such tools. More particularly theinvention relates to transparent overlays having inscribed thereon atool, such as 4an end wrench, in positions representing required spacefor movement for manipulating a fastening such as a screw threaded nutwhereby a draftsman may determine accessibility and operability of suchtool when applied to such a nut in relation to the surrounding structureof the design.

ln particular the invention relates to an overlay in the form of atransparent sheet on which are shown scaled views of a hand or handholding a tool in a task oriented position, plus manipulation spacerequired, if any, to be used in checking a drawing of a componentrequiring provision for application of a tool and the manual operationthereof, so that in the drawing stage of design it can be determinedwhether adequate space allowances have been made.L

An object of the invention is to provide the designer of componentsrequirin.n subsequent manual tasks in the assembly, disassembly andservici g thereof, with a device capable of ready application to adesign, while in the design stage, whereby the designer may readilyvisualize-and check the design for space required for application ofhand tools in the subsequent assembly of the components, or servicing ofthe completed structure. The device is preferably based on standardtools used in assembly and servicing, so that the design can beperfected in a manner such that its assembly or servicing may be`atfected by a standard tool, rendering it unnecessary, as in theservicing field particularly, to provide special tools for the purpose.

More specifically the invention has to do with providing the designerwith the means whereby account can be talten of a design in progress inrelation to the space required for the application of tools of astandard form in the ultimate assembly or servicing of the componentform in the ultimate assembly or servicing of the component subject ofthe design, whereby the final design, when aS- sembled and erected willhave adequate space for access for such tools, as wrenches, which may berequired in the assembly or servicin 7 of the apparatus. lt isparticularly desirable tr at apparatus be so designed as to be capableof being serviced with standard tools, and that-the number of specialtools for such servicing be ltept to a minimum, or eliminated. Advanceconsideration, during the design stages, of such problems may be readilyhad through employment of devices embodying the novel concepts of thepresent invention. in practice the invention may consist of a set oftransparent overlays based on a particular scale, one overlay beingprovided, for example, for each of a selected range of end wrench sizesof a standard design. Each overlay may have inscribed thereon a Wrenchshown in two positions to illustrate the necessary wrench movement intightening or loosening a threaded fastening such as a standard nut towhich the wrench is adapted, the wrench being shown as in the normalgrasp of an operators hand to show the overall clearance required foradequate manipulation, of both the wrench and operators hand.

The above and other novel features of the invention will appear morefully hereinafter from the following detailed description when taken inconjunction with the accompanying drawings. It is expressly understoodthat the drawings are employed for purposes of illustration only and arenot designed as a deinition of the limits of the invention, referencebeing had for this purpose to the appended claims.

In the drawings wherein like reference characters indicate like parts:

FIGURE l is a plan view of one transparent overlay, of a set ofoverlays, adapted for use in connection with a standard nut size andstandard wrench as indicated in the legendary material, and for use inchecking assembly and component drawings having the scale indicated.

FlG URE 2 is a plan view of a fragmentary portion of the overlay ofFGURE l suitably oriented and applied over a drawing of a device havinga nut shown in end elevation; and

FIGURE 3 is a plan View of another portion of the overlay of FlGURE 1suitably oriented and applied over a side elevational drawing of thesame device of FIGURE 2, and the side elevation of the same nut.

in FGURE l of the drawings there is shown a transparent sheet ofmaterial Ztl, which may be rectangular, and of Plexiglas, Celluloid orother transparent material of a stable character and non-shrinking. Uponthe transparency which may be referred to as an overlay, there isinscribed, in what may be referred to as a plan View, an

open end wrench 22 of a standard design, and in which Y the outline ofthe jaw faces 24 and 26 are parallel, and the planes thereof disposed atan angle of 15 from the axis of the handle 3l?. Gripping the handle in atypical manner is a right hand 3l, which embraces the end 32 of thewrench. The hand is extended to include a portion of the wrist as at 3d,and the grip is between the thumb 35 and foreiingers 3d wrapped aroundthe handle. A hexagonal nut 52, shown in outline form is also inscribed,and the center thereof may have a circular hole l pierced through theoverlay.

Since the more usual wrench applications contemplate hexagonal threadedfastenings, the swing of a wrench, having a 15 angle between the faces24.2 and Z6 and the handle axis 28 must be not less than 30, since byturning the wrench over, the 15 angle between the faces 24 and 26 andthe handle axis permits the wrench to grip new faces of a hexagonal nut,after rotation of the nut 30, so that the nut may be advanced in 30degree increments. Thus to loosen or tighten a nut, there must beprovided swing space for the wrench handle through an angle at least asgreat as 30, plus an additional angle suliicient to accommodate thewrench operators hand in closed gripping formation around the wrenchhandle end, and there should also be provision for any lost motion dueto the normal clearance between the jaw faces 2.4i and 26, and theengaged opposite faces of the hexagonal nut 62.

Upon the overlay there is also inscribed the wrench in a second positionwith its axis 28', disposed 30 from the rst position indicated by theaxis 23, the wrench handle being indicated at Sil' and the wrenchgripping hand being indicated at 3l. It can be seen, that to swing thewrench through 30, angular space must be provided as is indicatedbetween the lines indicated at ttl and 42, which embrace the outsidedimension of the hand in the grip formation outlined in the twopositions indicated.V

On the overlay there may also be indicated a fragmentary portion or" thewrench handle as at 30, with its taxis 2d disposed 521/2 degrees fromthe axis 2li, such angle being that required for the swing of a wrenchhaving `a 15 angle between the faces 2liand 26 and the handle axis 2S,when employed in tightening or loosening square headed nuts andfastenings. The angle between line fill, and line 43 serves to indicatethe space required by the hand and wrench to rotate a square nut through521/2 nj degrees. The lines di?, 42 and d3, may if desired, be inscribedupon the overlay. lf desired a portion of each of lines dii, i2 and i3may be a pencil slot as indicated at 39, 4i and 45, so that the designercan readily apply the lines as lines to a drawing.

Upon the overlay may also oe inscribed in outline' form, the'wrench 22in what may be referred to as a side elevation as at 60, the wrenchbeing shown applied to a hexagonal nut 62, with its axis indicated as at64. The free end of the wrench is shown embraced by the in Vscribedoutline 6o of the right hand in normal gripping relation thereto, theoutline being adapted to show the up and down clearance required for thewrench and the operators hand for the wrench application shown.

Upon the overlay, as at 7i), is shown what may be referred to as an endelevational view, with the inscribed outline' l'tl of a hand and aninscribed outline 74 of the wrist, the hand grasping the same wrench 22,and at 76' and It are shown inscribed the outlines ot the hand grippingthe wrench displaced as would occur upon moving the active jaw end ofthe wrench handle through an angle of or 521/2 respectively about theaxis indicated at 76 as would occur in turning the nut 62, through 36 or52.5 the latter angle being necessary for a nut having asquare head.

In FlGURES 2 and 3 are shown a typical end elevational view, and asectional view thereof, ot a layout drawing, of a device having a pippeline having a hexagonal pipe hitting nut and piping enclosed in ahousing having a top wall 82, end wall 83, side walls Se and 86, and abottom Wall 88. yThe end wall has been drawn as cut away by the designeras at 93 to provide an access opening to reach the nut Se, and would inpractice be provided with a'. dat removable cover plate, not indicated,which would be applied to close the housing opening.

An application ot' the overlay outline of FGURE l,V

suitably oriented, is shown in FlGURI-E 3,y to illustrate how the layoutdesigner may quickly determine by use. of the side elevational outlineof the overlay, the feasibility of the design, when a standard wrench n@for tightening or loosening the pipe nut S is to be accommodated byinserting the Wrench through the opem'ng 9i). VIn FlG- URE 2, the planview portion of the overlay has been laid over the end elevationdrawn'by the designer to indicate kwhether there is sufiicient openingto permit the required 30 of wrench swing, plus the space required bythe operators hand, the total angle being that between lines and 42. Ineither FGURE 2 and 3, without recourse to the overlay, it might appearto the designer, that the nut would be suiciently accessible to astandard f wrench through the opening provided at 9d. ln FlGURE 2 thereis a space sufficient for a 30 swing for astandard wrench handle, butnot when gripped in a normal manner by the hand of -an operator. Thedesigner can at once see that some change should be made in the housingdesign. By cutting away a portion ot the bottom plate as bracketed at 92and a portion of the side plates as bracketed at 94 and 9d, adequateopening space could be provided. All that the designer need do is toprovide such an enlarged opening, and provide a closure member that willhave opposite side portions, and a bottom portion as well as the .endportion to close the aperture.

Thus the designer is able to quickly observe the requirements, and checkhis design, and provide a design, wherein a Wrench of a specied standardform when held by a hand no larger than 95 percentile in size, caneasily service the nut shown.

Referring again to FIGURE 3, it can be seen that in Vorder to provide aproper grip upon the wrench there shown, the ingers 33 of the hand musthave clearance from the opening edge 37 of the housing bottom S6, and

the clearance thus necessitated, places the Wrench at an awkward anglein respect to the axis and location of the nut Stb'within the housing.By eliminating a portion of the bottom plate as indicated by the bracket92, the

Wrench axis may be swung around so as to extend from the nut at a morefavorable angle approaching to the axis of the nut Si?.

In FIGURE 2, by removing portions of the side walls, as indicated by thebrackets 9dand 96, the portion of the side wall Se to be removed,being'indicated by the broken line 93 in FGURE 3, it can be seen fromthe overlay that adequate clearance for the hand and wrench to swingthrough an angie ot 30 is provided. The aperture l in the overlay is ofsufficient diameter to allow a pencil point or a divider or otherpointed object to extend therethrough to act as a centering pin, so thatthe overlay may be swung angularly over a drawing to determine the bestmanner in which to provide the ncessary clearance in the housing layoutdesign for the application of the necessary tool required for assembly,or service, when the item under design subsequently reaches the erectionor production stage.y

The uses for the end elevational outlines 7d, 'ti' and 7G" of the handgripped wrench, which quickly show the space requirements for a 39 or525i/2 throw of the wrench will readily appear from the foregoing, itbeing necessary to provide room for the hand that holds the wrench atthe beginning of the throw, as well as at the end of the throw, plusadditional room the outlines itl and 7d' showing such end positions fora 36 wrench throw, and iti and 7G showing the end positions tor a 521/2wrench throw.

Each of the nuts shown in the overlay of FEGURE l me of the same sizeand as indicated, the overlay will preferably indicate the size ot thenut to which it is adapted, the rnalre of wrench such as the fictitioustrade name crattool, and the percentile of hand sizes embraced by thehand outlines, which in this case may be selected as 95th percentile,which means that the outlines of the hands shown on the overlay, iihaving a scale of l"=l, or full size, will be suii'iciently large toaccommodate 95 Zo of the hands of the workers who may be expected toengage in erection or servicing of the constructions under design.

The invention when applied to wrenches contemplates a set or overlaysfor each standard size wrench at scales commonly used such as lzl, 1:2,1:4 etc. For example a set of overlays for full scale, that is lil use,will embody hand outlines statisticly scaled at full size at thepercentile selected, out will vary in the wrench size outlined. Th'ewrench size illustrated is designated in the legendary matter in the boxas a 9/15" wrench.

In preparing the overlays with the inscribed wrench in the grasp of anoperator, it is essential to employ a hand size suh'iciently large sothat the vast majority of operators who may be expected to manipulatethe particularV tooll in the space to be provided, will be accommodated.For this purpose itis desirable that the grasping hand inscribed in theoverlays be based on a fairly high percentile hand and wrist ofanthropornetric measurements. Such a hand size may be derived from aparticular source such as H. T. E. Hertzberg, D. S. Baniels and E.Churchill in Anthropometry of Flying Personnel, l95, Technical Report52-321, Wright Air Development Center, and the source thereof may beindicated upon each overlay together Vwith the percentile used inoutlining the Wrench gripping hand inscribed on the overlay. In additionthe wrench size, the trade name if any, and the scale are indicated, inthe box in the lower right corner ot FIGURE l.

lt will of course be apparent that the overlays are designed for righthand use. Should it seem desirable to take into consideration the use ofa tool held by a left hand, the overlay may be turned over. While thenut, for example in the plan view of the overlay is shown with its flatsoriented transversely, it will be understood that the nut, after havingbeen turned 30, will require the wrench to be inverted. The wrench couldbe shown in such position also, but by reason of the centering aperture18 being in line with the centerline 28 of the tool, such a view is notessential, since the grip on the wrench would vary little when inverted.

The various views may be also used to indicate the space requirementsfor other tools such as a screwdriver, assuming the handle would have acomparable shape. The grip of a screwdriver handle would not necessarilyenlarge the hand outline to any great extent, and overlay may beemployed to indicate whether suiiicient room has been provided tomanipulate such a tool of a standard length.

While only one form of the invention has been illustrated, it is to beunderstood that the invention is not limited thereto. As various changesin the construction and arangement may be made without departing fromthe spirit of the invention, as will be apparent 4to those skilled inthe art, reference will be had to the appended claims for a definitionof the limits of the invention,

What is claimed is:

1. As an article of manufacture, a substantially transparent sheet ofmaterial for use over a drawing of a detail of a component of anassembly having a part such as the head end of a threaded fasteningrequiring the application of a hand tool in the ultimate assembly orservicing of the component, said sheet of material having stiffness, andsaid sheet of material having inscribed thereon the outline of the headend of a threaded fastening to which a standard tool is to be appliedfor rotating the fastening, and an outline of a standard tool inengagement therewith in the normal grip of an operators hand of aselected percentile in plan view whereby the space requirements for saidtool and an operators hand may be quickly cheeked against the componentdesign for actuation of the threaded fastening thereof, said sheethaving narrow linear slots disposed on lines closely embracing theoutline of the operators hand and converging at the center of the headend of the threaded fastening.

2. As an article of manufacture, a substantially transparent sheet ofmaterial for use over a drawing of a detail of a component of anassembly having a part such as the wrench head end of a threadedfastening requiring manipulation in the ultimate assembly or servicingof the component by a standard size tool such as a standard wrench ofcorresponding size to determine space requirement for tool movement,said sheet of material having stiffness, and said sheet of materialhaving inscribed thereon the outline of the wrench head end of athreaded fastening with aperture means to indicate the center thereof,and two outlines in plan View of a standard tool in engagement therewithin the grip of an operators hand of a selected percentile in twopositions designating the range of movement of the tool and hand outlinerequired for manipulation of the fastening whereby the spacerequirements for said tool in the grip of an operators hand may bequickly checked against the component design for actuating the threadedfastening thereof.

3. As an article of manufacture, a substantially transparent sheet ofmaterial for use over a drawing of a detail of a component of anassembly having a part such as the wrench head end of a threadedfastening requiring manipulation in the ultimate assembly or servicingof the component by a standard size tool such as a standard wrench ofcorresponding size to determine space requirement for tool movement,said sheet of material having stiffness, and said sheet of materialhaving inscribed thereon the outline of the Wrench head end of athreaded fastening in end elevation and aperture means to indicate thecenter thereof, and a first outline in plan View inscribed -thereon of astandard tool in engagement with said fastening in the grip of anoperators hand of a selected percentile, said overlay having inscribedthereon a second outline in plan View of the same tool in the same gripof the said operators hand angularly disposed about the said centermeans from said first outline by an angle representing not less than theminimum angular increment of movement of the tool required in thecontinued loosening or tightening of a threaded fastening membercorresponding to the inscribed fastening outline whereby the spacerequirements for said tool in the grip of an operators hand may bequickly checked against the component design for actuating the threadedfastening thereof.

4. As an article of manufacture, a substantially transparent sheet ofmaterial for use over a drawing of a detail of a component of anassembly having a part such as the polygonal wrench head end of athreaded fastening requiring manipulation in the ultimate assembly orservicing of the component by a standard size tool such as a standardwrench of corresponding size to determine space requirements for toolmovement, said sheet of material having stiffness, and said sheet ofmaterial having inscribed thereon the outline of the polygonal wrenchhead end of a threaded fastening in end elevation said sheet having anaperture at the center of the threaded fastening and said sheet havinginscribed thereon a irst outline in plan view of a standard tool inengagement with the fastening in the grip of an operators hand of aselected percentile, said overlay having inscribed thereon a secondoutline in plan view of the same tool in the same grip of the saidoperators hand angularly disposed about said aperture from said firstoutline by an angle representing not less than the minimum angularincrement of movement of the tool required in the continued loosening ortightening of a threaded fastening member corresponding to the inscribedfastening outline whereby the space requirements for said tool in thegrip of an operators hand may be quickly checked against the componentdesign for actuating the threaded fastening thereof.

References Cited in the tile of this patent UNITED STATES PATENTS1,519,965 Hovannessian Dec. 16, 1924 1,622,445 Jefferson Mar. 29, 19272,495,975 Kelly Jan. 31, 1950

1. AS AN ARTICLE OF MANUFACTURE, A SUBSTANTIALLY TRANSPARENT SHEET OFMATERIAL FOR USE OVER A DRAWING OF A DETAIL OF A COMPONENT OF ANASSEMBLY HAVING A PART SUCH AS THE HEAD END OF A THREADED FASTENINGREQUIRING THE APPLICATION OF A HAND TOOL IN THE ULTIMATE ASSEMBLY ORSERVICING OF THE COMPONENT, SAID SHEET OF MATERIAL HAVING STIFFNESS, ANDSAID SHEET OF MATERIAL HAVING INSCRIBED THEREON THE OUTLINE OF THE HEADEND OF A THREADED FASTENING TO WHICH A STANDARD TOOL IS TO BE APPLIEDFOR ROTATING THE FASTENING, AND AN OUTLINE OF A STANDARD TOOL INENGAGEMENT THEREWITH IN THE NORMAL GRIP OF AN OPERATOR''S HAND OF ASELECTED PERCENTILE IN PLAN VIEW WHEREBY THE SPACE REQUIREMENTS FOR SAIDTOOL AND AN OPERATOR''S HAND MAY BE QUICKLY CHECKED AGAINST THECOMPONENT DESIGN FOR ACTUATION OF THE THREADED FASTENING THEREOF, SAIDSHEET HAVING NARROW LINEAR SLOTS DISPOSED ON LINES CLOSELY EMBRACING THEOUTLINE OF THE OPERATOR''S HAND AND CONVERGING AT THE CENTER OF THE HEADEND OF THE THREADED FASTENING.